Nb3Sn超导复合股线临界电流与纤维损伤耦合作用的研究

项目名称： Nb3Sn超导复合股线临界电流与纤维损伤耦合作用的研究

项目编号： No.11302119

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 罗威

作者单位： 三峡大学

项目金额： 29万元

中文摘要： Nb3Sn超导股线是超导纤维与多层金属基底构成的复合线材，具有优良的超导性能，在ITER 磁体系统及其它强磁场工程中有着重要应用。由于Nb3Sn是典型的脆性材料，股线中的超导纤维极易发生损伤，其临界电流对其所处的应力应变状态极为敏感，在复杂的热-电-磁-液压服役条件下，Nb3Sn超导股线临界电流和纤维损伤之间具有复杂的力-电耦合机制，正确揭示和刻画两者之间的耦合作用是预测股线有效性能的关键。本项目拟针对不同方法制备的Nb3Sn超导股线，建立不同应变模式下纤维损伤的形成和演化模型；在此基础上，对于不同类型的裂纹和裂纹分布，实现裂纹处超导电流重新分布以及纤维间电流重新传递机制的定量分析和模拟；同时，考虑临界电流退化导致的股线所处应力状态的改变，进而分析其对纤维损伤演化发展的影响；从而准确和有效刻画Nb3Sn超导股线临界电流与纤维损伤的耦合作用，并与已有实验结果对比以验证模型和分析方法的有效性。

中文关键词： Nb3Sn超导复合股线；临界电流密度；统计强度；CICC；临界速度

英文摘要： Nb3Sn superconducting composite strands composed of superconducting filaments and a multilayered metal matrix have excellent superconducting properties so have important applications in ITER magnetic system and other high magnetic field engineering. Because Nb3Sn is a typical brittle material, the damage of the superconducting filaments in strands are easily produced, and the critical current of strands is very sensitive to the strain and stress states of strands. Under the complicated thermal-electrical-magnetic-hydraulic service conditions, the critical current and filament damage of Nb3Sn strands possess a complicated electro-mechanical coupling mechanism. Thus, to predict the effective properties of strands, it is very important to accurately reveal and depict the coupling between the critical current and filament damage of Nb3Sn strands. In the proposed program, the initiation and evaluation model of filament damage under different strain modes for various routine produced Nb3Sn strands will be developed; on this basis, to different types of cracks and different crack distributions, the superconducting current redistribution at crack and the current transfer between filaments will be analyzed and simulated quantitatively; simultaneously, considering the change of the stress state of strands due to the degra

英文关键词： Nb3Sn superconducting composite strand；critical current density；statistic strength； CICC；critical velocity